Sorry, forgot to mention that part.  I've formatted the individual plots as a list and a set,, and still no go; only a different error message.

It says:

Error, (in plots/object2plot) cannot display object with name INTERFACE_PLOT3D, as dimension cannot be determined

This same approach, however, works in the same context (only with different functions) elsewhere in the same worksheet with the format:

display(F1, F2, F3, title="" etc).